Side-pull rotary mower-conditioners typically use a tongue swing cylinder mounted to the right of the tongue pivot. Thus, in order to swing the tongue outwardly to a normal working position where the towing tractor travels a path to the left of the standing crop being cut by the mower-conditioner, the cylinder must be extended from a fully retracted position, which it occupies when the tongue is in a central position for permitting the transport of the mower-conditioner.
This cylinder placement makes it difficult to have a low-cost lock for transport, as is necessary for holding the cylinder in its retracted position. It is also difficult to provide multiple fixed operating positions, which are achieved by placing the cylinder in extended positions. With the prior art cylinder position, an external mechanical device is provided that stops movement of the tongue by locking it to the carrier frame. Multiple operating positions are achieved by selectively repositioning the cylinder by removing the cylinder mounting pins and placing them in alternate sets of mounting holes.
While it is known to provide a mower-conditioner with a tongue having its rear end pivotally mounted to a forward projection of the main frame located at the left side of the header, and to provide an extensible and retractable hydraulic cylinder at the left side of the tongue pivot, this location of the tongue has the disadvantage that it adds to the overall transport width of the mower-conditioner.